The present invention relates to a semiconductor device that has a photo-detection element and a signal processing section, and in particular to a semiconductor device for optical communications, which is installed in an electronic apparatus of, for example, a TV (television set), a VTR (video tape recorder), an audio component or an air conditioner, and which generates a control signal for controlling the operation of each electronic apparatus by receiving an infrared ray signal from a transmitter. The present invention relates also to the electronic apparatus provided with the above-stated semiconductor device.
As shown in the front view of FIG. 8A, the side view of FIG. 8B and the side sectional view of FIG. 8C, a conventional semiconductor device for optical communications has a lead frame 101, a photo-detection chip 102 and a control IC chip 103 mounted on the lead frame 101, a first sealing portion 110 made of an infrared transmitting resin, which portion 110 seals the photo-detection chip 102 and the control IC chip 103 and has a lens portion 111, and a second sealing portion 120 made of a conductive resin, which portion 120 covers the first sealing portion 110 except for the lens portion 111 (refer to JP H09-84162 A)
The conventional semiconductor device for optical communications receives control signals transmitted from the transmitter by infrared rays to control a variety of electronic apparatuses. Since the signals transmitted by infrared rays are very feeble, a high-gain amplifier is built into the semiconductor device for optical communications. The optical signals of the infrared rays are amplified by this amplifier, and thereafter the optical signal is converted into a digital signal to be output. Thus, the semiconductor device for optical communications is very sensitive to noise.
Accordingly, as an anti-noise measure in the conventional semiconductor device for optical communications, noise is removed by covering the first sealing portion 110 with the second sealing portion 120 except for the lens portion 111 corresponding to the photo-detection region and by electrically connecting the second sealing portion 120 to a GND terminal of the lead frame 101.
However, there are a wide variety of conventional electronic apparatuses equipped with the semiconductor devices for optical communications. The above-sated anti-noise measure in the conventional semiconductor device for optical communications has disadvantageously been insufficient, particularly when the conventional semiconductor device for optical communications is installed in an electronic apparatus (TV or the like) having intense electromagnetic noise.